﻿using Ganss.XSS;
using Microsoft.AspNetCore.Mvc.Filters;
using System;

namespace Qy.Common
{
    class XssFilterUtility
    {

        private readonly HtmlSanitizer sanitizer;
        public XssFilterUtility()
        {
            sanitizer = new HtmlSanitizer();
            //sanitizer.AllowedTags.Add("div");//标签白名单
            sanitizer.AllowedAttributes.Add("class");//标签属性白名单,默认没有class标签属性
                                                     //sanitizer.AllowedCssProperties.Add("font-family");//CSS属性白名单
        }

        /// <summary>
        /// XSS过滤
        /// </summary>
        /// <param name="html">html代码</param>
        /// <returns>过滤结果</returns>
        public string Filter(string html)
        {
            string str = sanitizer.Sanitize(html);
            return str;
        }

    }


    public class XssFieldFilterAttribute : Attribute, IActionFilter
    {
        private readonly XssFilterUtility xss;
        public XssFieldFilterAttribute()
        {
            xss = new XssFilterUtility();
        }

        //在Action方法之回之后调用
        public void OnActionExecuted(ActionExecutedContext context)
        {

        }

        //在调用Action方法之前调用
        public void OnActionExecuting(ActionExecutingContext context)
        {
            //获取Action参数集合
            var ps = context.ActionDescriptor.Parameters;
            //遍历参数集合
            foreach (var p in ps)
            {
                //if (context.ActionArguments[p.Name] != null)
                //{
                //当参数等于字符串
                if (p.ParameterType.Equals(typeof(string)))
                {
                    context.ActionArguments[p.Name] = xss.Filter(context.ActionArguments[p.Name].ToString());
                }
                else if (p.ParameterType.IsClass)//当参数等于类
                {
                    ModelXssFieldFilter(p.Name, p.ParameterType, context.ActionArguments[p.Name]);
                }
                // }

            }
        }

        /// <summary>
        /// 遍历修改类的字符串属性
        /// </summary>
        /// <param name="key">类名</param>
        /// <param name="t">数据类型</param>
        /// <param name="obj">对象</param>
        /// <returns></returns>
        private object ModelXssFieldFilter(string key, Type t, object obj)
        {
            //获取类的属性集合
            // var ats = t.GetCustomAttributes(typeof(XssFieldFilterAttribute), false);


            if (obj != null)
            {
                //获取类的属性集合
                var pps = t.GetProperties();

                foreach (var pp in pps)
                {
                    if (pp.GetValue(obj) != null)
                    {
                        //当属性等于字符串
                        if (pp.PropertyType.Equals(typeof(string)))
                        {
                            string value = pp.GetValue(obj).ToString();
                            pp.SetValue(obj, xss.Filter(value));
                        }
                        else if (pp.PropertyType.IsClass)//当属性等于类进行递归
                        {
                            pp.SetValue(obj, ModelXssFieldFilter(pp.Name, pp.PropertyType, pp.GetValue(obj)));
                        }
                    }

                }
            }

            return obj;
        }
    }
}
